The present invention relates to a cathode-ray tube dividing apparatus and a cathode-ray tube dividing method most suitable to disassemble a cathode-ray tube (CRT) into pieces for recycling.
Recently, the spotlight has been focused on recycling of resources and prevention of environmental destruction. To meet such a demand, studies have been extensively made to reuse displays, typically cathode-ray tubes (Braun tubes) of used television sets and computer monitors. In particular, it has been of urgent necessity to rapidly and efficiently reuse disposed television sets which has been progressively increased.
A cathode-ray tube, used as an image receiver incorporated in a television set or the like, is a glass structure composed of a panel portion (also called as a face portion) and a funnel portion (also called as a panel skirt portion). The panel portion is made from a substantially transparent glass material for improving light transmittance, and the funnel portion is made from a glass material in which lead is mixed for preventing leakage of X-rays caused by collision of electron beams accelerated at a high voltage with a substance. The funnel portion and the panel portion are welded in a shield fashion to each other with frit glass (solder glass) into a tube shape.
Outwardly, an electron gun, a deflection yoke and the like are mounted on the external rear side of a cathode-ray tube, and a shadow mask (or aperture grill) is provided in the cathode-ray tube. A fluorescent screen provided on the inner surface side of the panel portion is regularly coated with phosphors of three colors (red, green and blue).
A method of recycling a cathode-ray tube of this type has been disclosed, for example, in Japanese Patent Laid-open No. Hei.9-171773, in which the cathode-ray tube is divided into a panel portion and a funnel portion by pressing heat wires on side surfaces of the cathode-ray tube. The heat wires are moved to the side surfaces of the cathode-ray tube by a motor and are pressed on the side surfaces of the cathode-ray tube.
The above heat wire pressing method, however, has a problem. Under the present circumstances, the method includes the steps of generating cracks at dividing glass portions by applying an electrical power to the heat wires in accordance with an energizing condition in which a power amount and an energizing time are made constant irrespective of the size of a cathode-ray tube, and after generation of cracks, tapping four corners of the cathode ray-tube, on which the heat wires are not pressed, with a tool such as a chisel to grow the cracks thus generated to such an extent as to certainly, easily divide the cathode-ray tube. If an electrical power being large enough to allow cracks generated on the four sides to come to be linked to each other at the four corners is applied to the heat wires, cracks may be too rapidly generated to induce cracking of portions other than the desirable portions on which the heat wires are pressed, for example, inside the glass portions on the funnel and/or the panel. To prevent such an inconvenience as well as to ensure the division, the growth of cracks is made by the next step of tapping the corners of the cathode-ray tube with a tool such as a chisel. Accordingly, the related art cathode-ray tube dividing apparatus is configured such that:
(1) the amount of power is suppressed at a small value; and PA1 (2) the function of tapping on four corners with a tool such as a chisel is provided, so that such an apparatus has a problem that it takes a lot of time to divide a cathode-ray tube. The increased time required to divide one cathode-ray tube means that the number of the dividing apparatuses required to divide a specific number of cathode-ray tubes is increased, to thereby raise the recycling cost of the cathode-ray tubes.